High speed circuit closing device



an) I My HIGH SPEED CIRCUIT CLOSING DEVICE Filed June 6, 1960 United States Patent 3,103,569 HIGH SPEED ClRCUIT CLOSING DEVICE Erich Reichardt, Berlin-Spandau, Germany, assignor to Siemens-Schuckertwerke A.G., Berlin, Germany, a corporation of Germany Filed June 6, 1969, Ser. No. 34,040 Claims priority, application Germany June 5, 1959 6 Claims. (Cl. 200-463) This invention relates to a high speed contact device and, more specifically, relates to a high speed short circuiter for short circuiting electrical equipment responsive to fault conditions, wherein the short circuiting device is substantially free of contact bounce and provides a substantial high pressure contact area. Short circuiters are well known in the art and have been described, for example, in US. Patent 2,888,538 entitled Explosive Type Short Circuiter, in the name of Otto Jensen. This patent illustrates the manner in which a short circuiter can be used specifically in connection with rectifying elements, whereby the rectifying elements are short clrcuited and, thus, protected during fault conditions.

Other illustrations of high speed short circuiters are shown in US. Patent 2,930,870 to W. Baer entitled High Speed Switch. A typical application of these devices is shown in co-pending application, Serial No. 641,108, filed February 19, 1957, in the name of E. J. Diebold and entitled Instantaneous Trip for Rectifier Protection, now Patent No. 2,891,130; June 16, 1959.

In-these short circuiter type devices a movable contact element is movable into engagement with a plurality of electrically insulated stationary contacts, each of which are terminals of a conductor of the circuit. When the movable contact is moved to its engaged position, it electrically interconnects all of the insulated stationary contacts whereby the conductors with which they are associated are electrically interconnected and circuit elements such as rectifiers within the circuitry are short circui-ted. In accordance with the present invention, the stationary contact devices are disposed along a conical surface defining a conically shaped opening. The movable contact" has a truncated conical shape which cooperates with the shape of the conical opening formed by the stationary contacts. When the movable contact moves to its en gaged position, the engagement occurs around the surface of a cone.

In order to prevent contact bounce, and to permit a substantial area of high pressure engagement between the movable contact and the cooperating stationary contacts, the engaging surfaces of the stationary contacts are provided with grooves, While the engaging surface of the movable contact is provided with grooves which are at an angle such as 90 to the grooves of the stationary contact. The contact material of the grooves of at least either the movable contact or the stationary contacts is relatively soft, whereby when the cooperating contacts engage the soft grooves of the said, one contact deforms to absorb the engaging energy during the contact engaging operation. Accordingly, there will be no bounce during contact engagement.

Furthermore, and because of this deformation, there will be a substantial and intimate high pressure contact area between the cooperating contacts so that the re sistance of the short circuit patent is kept to an absolute Accordingly, a primary object of this invention is to provide a novel short circuiter device, wherein bouncing is prevented during contact engagement.

Another object of this invention is to provide a novel contact device for short circuiting operation, wherein substantial contact area is provided.

hlhfifihh Patented Sept. 10, 1963 A further object of this invention is to provide a novel short circuiter device, wherein the cooperating contacts are grooved with the grooves of one contact being at an angle to the grooves of the other and at least one of the grooved contacts being of relatively soft material, whereby deformation during contact engagement absorbs bounce energy and permits intimate high pressure contact engagement.

Another object of this invention is to provide a novel short circuiter device,- wherein the movable contact is conically shaped and cooperates with conically disposed stationary contacts, whereby the contacting areas of the cooperating contacts are grooved with the grooves of one of the contacts, being perpendicular to the grooves of the other of the contacts.

These and other objects of my invention will become apparent from the following description taken in conjunction with the drawings in which:

FIGURE 1 shows a side view partially in cross section of the short'circuiter of the invention.

FIGURE 2 shows a side plan view of the embodiment of FIGURE 1 when seen from the left-hand side of FIGURE 1. 7

Referring now to FIGURES 1 and 2, these stationary contacts 10, 11 and 12 are carried by an insulating hous ing 13 as by supporting the contact within insulator plates 14, 15 and 16 for contacts 10, 11 and 12 respectively and then securing the plates to housing 13 as by bolts such as bolts 16 and 17 for plate 14. Note that in the construction of bolt 17 which is typical of all ofthe bolt means the bolt is threaded into an insert such as insert 18 for an opening in insulating body 13. Clearly, however, the stationary contacts 10, 11 and 12 may be secured to a support body such as body 13 in any desired manner. The interior contacting surfaces of stationary contacts 10, 1.1 and 12 define the surface of a cone having an angle with respect to the axis of the device which is preferably less than ten degrees.

The engaging surfaces are then provided with grooves which are perpendicular to the axis of the short circuiter such as grooves 19 and 20 for contacts 19 and 11 respectively. It will be noted that only three stationary contacts 10, 11 and 1-2 have been shown in the preferred embodiment. It will, however, be apparent to those skilled in the art that any number of stationary contacts could be used depending upon the number of conductors which are to be electrically interconnected during the short circuiting operation. v The movable contactstructure is carried by a housing 20 which may be of metal. The housing 20 carries -a movable contact rod 211 which is movable along its axis and is terminated by movable contact 22 which has a truncated cone configuration having an angle similar to the angle of the cone defined by the stationary contacts 10, 11 and 12. The contacting surface of movable contact 22 is grooved as by grooves 23 which are at an angle to grooves 19 and 20 of the stationary contacts and is preferably perpendicular thereto as shown. It will be noted that at least the stationary contacts 10, 11 and 12 are of relatively soft material, while the movable contact 22 may be of either relatively soft material or relatively hard material.

The other end of contact rod 21 has a detent carrying means 24 connected thereto which has a detent 25 therein which receives latch 29 pivotally mounted on pivot 27. The latch mechanism which will be described more fully hereinafter is normally held in the position shown in FIGURE 1.' It will be noted that when in the disengaged position, the movable contact surface 28 is supported b shelf or guide 29 of insulating body 13.

The movable contact assembly is normally biased toward the left and against the latch force of latch 26 by ganged spring washers including end washers 3t) and 31 which are carried in cylinder 32. The cylinder 32, which is the spring housing, is connected to flange 33 of housing 20, as by welding and washer 30 bears against a shoulder 34 of movable contact 22 to achieve the biasing action. The insulating housing 13 and, thus, the stationary contacts are carried by flange 33 as by bolt means such as bolt 34. If desired, the same bolt means which includes bolt 34 can secure spring housing 32 and insulating housing 13 at one and the same time.

So long as latch 26 remains in the latched position shown, the movable contact 22 and rod 21 will remain in the disengaged positions shown. When, however, the latch is defeated, the powerful spring assembly, including the Belleviile type washers 30 and 3.1, will accelerate the movable contact 22 to the left at extremely high speed and cause contact engagement between movable contact 22 and stationary contacts 10, 11 and 12.

Because of the cooperating groove construction and, assuming at least that one of the movable contact or stationary contacts is of soft material, the grooves of the soft material will deform during the application of the extremely high closing force. This deformation will operate first to absorb the kinetic energy of the closing operation to prevent bounce and will additionally operate to permit intimate high pressure contact engagement between the cooperating contacts.

It will also be noted that the distance of contact motion and the length of guide surface 28 is such that surface 28 of contact 22 leaves the guide surface 29 of insulating body 13 before contact engagement occurs. Accordingly, the movable contact will be free to move in a transverse direction to its axis so that it can be selfseating when it engages the stationary contacts.

The manner in which latch 26 is controlled is as follows: A series of balls or rollers 40 are carried within housing 20 and are supported on all but one side by housing 20. They are aligned so that their centers are along a straight line. The free side of the balls 14 is closed by a movable plate 41 which is biased into engagement with the two center balls by biasing spring 42 which receives shaft 43 of plate 41. The biasing force of spring 42 is sufiicient to keep the balls 14 aligned and bearing directly upon the surface of latch 26 so that latch 26 remains in detent 25. That is to say, so long as the balls 40 are properly aligned, they appear to be a single rigid member to latch 26. A pin 44 passes through housing 20 and is positioned as shown at the center of the two center balls 40. When this pin is depressed or moved to the left, it will drive the two center balls to the left against the force of spring 42. This is like breaking a toggle whereby the spring force of the housing of Belleville washers such as washers 30 and 31 will cam latch 26 upwardly to cause a complete collapse of the ball arrangement, whereby an extremely high speed motion of rod 21 occurs to the left.

The novel latch arrangement set forth above is extremely advantageous in being mechanically simple and requiring a relatively small release force, although a relatively high force may be restrained by the latch. The pin 44 may, of course, be controlled in any appropriate manner as by a solenoid whereby the pin is moved to the left responsive to predetermined fault conditions which are to initiate the operation of the short circuiter device. By way of example, pin 44 may be coupled to the armature of a holding magnet which is normally restrained by a holding magnet which restrains the operation of a spring which biases pin 44 to the left. The armature of the holding magnet may then be magnetically arranged to be released responsive to a predetermined current condition in the circuit being protected or responsive to a signal from some measuring device, whereby the spring needed.

In the foregoing, I have described my invention only in connection with preferred embodiments thereof. Many variations and modifications'of the principles of my invention within the scope of the description herein are obvious. Accordingly, I prefer to be bound not by the specific disclosure herein but only by the appending claims.

I claim:

1. In a short circuiter, said short circuiter comprising a plurality of stationary contacts normally electrically insulated from one another and a relatively movable contact; each of said plurality of stationary contacts having a contact surface; said contact surfaces of said stationary contacts defining the peripheral surface of a truncated cone, complementary with respect to said movable contact; said movable contact having a conically shaped contact surface common to each of said contact surfaces of said plurality of stationary contacts; said conically shaped contact surface of said movable contact and said truncated cone defined by said stationary contact surfaces having a common axis; said movable contact being movable to an engaged position with said plurality of stationary contact along said axis; said contact surfaces of said stationary contacts having grooves; said contact surface of said movable contact having grooves; said grooves in said movable contact being transverse to said grooves in said plurality of stationary contacts.

2. The short circuiter of claim 1 wherein at least one of said movable contact or each of saidplurality of stationary contacts is formed of softer material than the other of said movable contact or each of said plurality of stationary contacts. 1

3. The short circuiter of claim 1 wherein the grooves in each of said plurality of stationary contacts are perpendicular to said axis and the grooves of said movable contact are in the same plane as said axis.

4. The short circuiter of claim 1 wherein said movable contact has guide means for guiding the motion of said movable contact toward said engaged position; said movable contact being rendered independent of said guide means immediately prior to engagement and being selfseating.

55. A contactor device; said contactor comprising a stationary contact and a movable contact; said stationary contact having a contact surface defining at least a peripheral portion of a cone; said movable contact having a contact surface defining at least a peripheral portion of a cone; said conically shaped contact surfaces of said movable contact and said stationary contact having a common axis; said movable contact being movable along said common axis to a contact engaged position; said contact surface of said stationary contact having grooves therein; said contact surface of said movable contact havmg grooves therein; said grooves of said movable contact being transverse to said grooves of said stationary contact; at least one of said stationary or movable contacts being of relatively soft material; the other of said stationary or movable contacts being of a relatively hard material.

7 6. A contactor device; said contactor comprising a stationary contact and a movable contact; said stationary contact having a contact surface defining at least a peripheral portion of a cone; said movable contact having a contact surface defining at least a peripheral portion of a cone; said conically shaped contact surfaces of said 5 movable contact and said stationary contact having :1 References Cited in the file of this patent common axis; said movable contact being movable along UNITED STATES PATENTS said common 8X18 to a contact engaged position; saidcontact surface of said stationary contact having grooves 9031927 Wendler 17, 1908 therein; said contact surface of said movable contact hav- 5 1,040,455 Tatum 1912 ing grooves therein; said grooves of said movable .con- 2,563,335 et 1951 tact being transverse to said grooves of said stationary 2,864,922 Kuu et a1 16, 1958 contact; said grooves in said movable contact being in the plane of said axis; said grooves in said stationary co-n- FOREIFHTI PATENTS tact being perpendicular to said axis. 10' 803,791 Great Brltalfl 8 

1. IN A SHORT CIRCUITER, SAID SHORT CIRCUITER COMPRISING A PLURALITY OF STATIONARY CONTACTS NORMALLY ELECTRICALLY INSULATED FROM ONE ANOTHER AND A RELATIVELY MOVABLE CONTACT; EACH OF SAID PLURALITY OF STATIONARY CONTACTS HAVING A CONTACT SURFACE; SAID CONTACT SURFACES OF SAID STATIONARY CONTACTS DEFINING THE PERIPHERAL SURFACE OF A TRUNCATED CONE, COMPLEMENTARY WITH RESPECT TO SAID MOVABLE CONTACT; SAID MOVABLE CONTACT HAVING A CONICALLY SHAPED CONTACT SURFACE COMMON TO EACH OF SAID CONTACT SURFACES OF SAID PLURALITY OF STATIONARY CONTACTS; SAID CONICALLY SHAPED CONTACT SURFACE OF SAID MOVABLE CONTACT AND SAID TRUNCATED CONE DEFINED BY SAID STATIONARY CONTACT SURFACES HAVING A COMMON AXIS; SAID MOVABLE CONTACT BEING MOVABLE TO AN ENGAGED POSITION WITH SAID PLURALITY OF STATIONARY CONTACT ALONG SAID AXIS; SAID CONTACT SURFACES OF SAID STATIONARY CONTACTS HAVING GROOVES; SAID CONTACT SURFACE OF SAID MOVABLE CONTACT HAVING GROOVES; SAID GROOVES IN SAID MOVABLE CONTACT BEING TRANSVERSE TO SAID GROOVES IN SAID PLURALITY OF STATIONARY CONTACTS. 